We propose to analyze in detail the sequence organization of the ribosomal protein genes of Saccharomyces cerevisiae. In addition, we propose to determine the nucleotide sequences at the 5' end of several of these coordinately controlled genes. Recombinant DNA molecules containing ribosomal protein genes will also be used as probes with which to measure the concentration of these ribosomal protein mRNAs under a variety of physiological and genetic circumstances. The sequence organization of the ribosomal protein genes of Drosophila melanogaster will be investigated as well in order to extend our knowledge of the organization of these genes to a metazoan eucaryote. We will continue our studies on the sequence organization of the yeast histone genes; the organization of these genes in yeast is unlike any other eucaryote described to date. We will attempt to map genetically and to determine the degree of linkage of the yeast histone genes and the yeast ribosomal genes.